Wartook Reservoir is located on the MacKenzie River in the central Grampians. It is the primary source of supply for Horsham and Natimuk, and a secondary source for Supply System 6 of the Wimmera Mallee Pipeline. The reservoir, which has a high recreational value, also provides important flows to the environment.
| Current Level | 440.920 m AHD |
| Current Volume | 22,370 ML |
| Percent Full | 76% |
| Current Inflows | 520 ML/week |
| 24 hour Rainfall | 6 mmCummulative Inflows Graph |
| Current Releases | 39 ML/day |
| Current Spills | 0 ML/day |
| Current Airspace | 6,930 ML |
| Full Supply Level | 441.68 m AHD |
| Full Supply Volume | 29,300 ML |
| Maximum Operating Volume | 29,300 ML |
| Spillway Volume | 441.83 m AHD |
| Spillway Length | 175 m |
| Spillway Capacity | 1,500 ML/day |
| Secondary Spillway Level | 442.10 m AHD |
| Secondary Spillway Length | 127 m |
| Secondary Spillway Capacity | 25,056 ML/day |
| Outlet Capacity | 500 ML/day |
| Catchment Area | 75 km2 |
| Surface Area When Full | 10.31 km2 |
| Major Tributary | MacKenzie River |
| Average Annual Inflow | 26,000 ML/year |
| Maximum Depth | 8.2 m |
| Year Constructed | 1887 |